Effect of herbimycin A on renal cancer cell growth

We investigated the effect of herbimycin A on the monolayer growth of 4 human renal cell carcinoma (RCC) cell lines and a normal renal tubular cell line (RTC 13) using MTT [3-(4,5-dimethylthiszol-2,5-diphenyl tetrazolium bromide)] assay. Herbimycin A induced remarkable growth inhibition in each RCC cell line tested, without any morphological changes of the cells. At the concentration of 500 ng/ml, herbimycin A caused more than a 30% growth inhibition in all RCC cells (p < 0.005 vs RTC 13), while less than 7% growth inhibition was observed in RTC 13 at the same herbimycin A concentration. The cell cycle was estimated by analysing DNA (deoxyribonucleic acid) content using a FACS. A DNA histogram of RCC cells treated at herbimycin A showed a block in the cell cycle at the S and G2M phases. However, little effect by herbimycin A on RTC 13 cells was observed. Our results suggest that protein tyrosine kinases inhibitors, like herbimycin A, may offer a new treatment option for RCC patients.     

Analysis of thermal stability of acrylonitrile-acrylic elastomer-styrene terpolymer in injection molding

Acrylonitrile-acrylic elastomer-styrene terpolymer (AAS resin) was developed to improve weatherability of acrylonitrile-butadiene-styrene terpolymer (ABS resin). To compare thermal stability of both resins, test parts of AAS and ABS resins were injection molded at various temperatures and the Izod impact value of the resulting moldings was measured. A study was then made to find the relationship between this value and deterioration of the resins. AAS resin was molded at temperatures from 180°C to 280°C. The impact value of the resulting moldings was almost constant for temperatures up to 260°C, with the first major decrease occurring at 280°C. In contrast, the impact value of conventional ABS resin moldings constantly decreased as the molding temperature was elevated. To explain this phenomenon in both resins, two types of test program steps were undertaken: (1) The cause of the change in characteristics of the AAS resin was determined by obtaining its stress-strain curve in a high-speed flexural strength test; measuring its infrared absorption spectrum; and determining its flow properties with a constant-pressure extrusion type rheometer; (2) the distribution of elastomer in the resin was observed with an electron microscope. It was found that the decrease of impact values of both resins at high temperatures is caused by deterionration of the elastomer. Also, it was found that the different relationships between the impact value and molding temperatures for AAS and ABS resins are due to the difference between the rates of thermal degradation of the acrylic elastomer and butadiene elastomer.     

Photon Emission in Self-Quenching Streamer Chambers

We have studied the properties of photons emitted by self-quenching streamer chambers. In particular the timing, intensity and wavelength distribution of these light pulses was measured with several gas mixtures.     

Arteriovenous differences in plasma concentrations of catechols in rats with neuropathic pain

BACKGROUND: Alterations in cutaneous temperature, sweating, and cutaneous blood flow in patients with pain states, such as reflex sympathetic dystrophy and causalgia, have been interpreted as evidence for exaggerated sympathetic outflow. It was determined whether pain behavior in a rat model of sympathetically maintained pain is associated with alterations in regional sympathoneural function. METHODS: Peripheral neuropathy was induced in 29 Sprague-Dawley rats by ligation of the left L5 and L6 spinal nerves. Sixteen other rats had sham surgery (nerve exposure without ligation). Animals were tested for behavioral signs of allodynia (decreased paw withdrawal thresholds to mechanical stimuli) at 2 and 4 weeks after the surgery. Arterial and iliac venous blood samples (left, affected; right, control) were obtained at 2 weeks (NP2, n = 14) and 4 weeks (NP4, n = 15) after neuropathic or sham (n = 8 at 2 and 4 weeks) surgery. Plasma concentrations of dihydroxyphenylalanine, dihydroxyphenylacetic acid, dopamine, norepinephrine, and the intraneuronal norepinephrine metabolite, 3,4-dihydroxyphenylglycol, were analyzed in arterial and left and right iliac venous samples. RESULTS: A decrease in paw withdrawal threshold was observed in neuropathic (NP2 and NP4) but not sham-operated rats. Affected and control limbs did not differ in arteriovenous differences in concentrations of dihydroxyphenylalanine, dihydroxyphenylacetic acid, dopamine, or 3,4-dihydroxyphenylglycol. No differences were observed between sham-operated and neuropathic animals in these arteriovenous increments. In contrast, affected limbs of NP2 rats had a reduced arteriovenous increment in norepinephrine concentrations, compared to that in the control side (P < 0.05). CONCLUSIONS: No neurochemical evidence of sympathetic hyperactivity is observed in the rat model of neuropathic pain; if anything, norepinephrine release is decreased in the affected limb. Autonomic disturbances in neuropathic pain are therefore more likely the result of receptor supersensitivity than increased local sympathoneural traffic.     

Cationic ring-opening polymerization of 2-substituted-2-oxazolines initiated by carbon black surface

Summary Carbon blacks were found capable of initiating the ringopening polymerization of 2-substituted-2-oxazolines at relativery high temperatures. The activation energy of the polymerization of 2-methyl-2-oxazoline was estimated to be 13.4 kcal/mol. Carbon black lost the initiating activity of the polymerization upon the blocking of carboxyl groups on the surface by the treatment with potassium hydroxide or diazomethane. Therefore, it was concluded that carboxyl groups on carbon black play an important role in the initiation of the polymerization. Furthermore, it was found that during the polymerization, poly(N-acylethyleneimine) was grafted onto carbon black by the termination of growing polymer chain with the surface.     

Antitumor response of genetically engineered IL-2 expression to human esophageal carcinoma cells in mature T cell-defective condition

We examined whether antitumor effect could be produced by retrovirally expressed human interleukin-2 (hIL-2) gene in human esophageal cancer cells (T.Tn) using immunocompromised nude mice. Loss of tumorigenicity of hIL-2-producing T.Tn (T.Tn/hIL-2) cells inoculated subcutaneously was observed in contrast to continuous tumor growth of wild-type cells, although in vitro proliferation of T.Tn/hIL-2 cells remained the same as that of wild-type cells. The antitumor effect was also evidenced by the injection of T.Tn/hIL-2 cells into established tumors of wild-type cells. The injection significantly retarded the subsequent growth of wild-type tumors. Histological examination of regressing T.Tn/hIL-2 cells revealed necrotic areas and infiltration of several types of inflammatory cells. Treatment of nude mice with anti-asialoGM1 antibody did not influence the IL-2-mediated tumor rejection. Vaccination of nude mice with irradiated T.Tn/hIL-2 cells whose secretion of hIL-2 in amount was comparable to that of unirradiated cells did not develop protective immunity. Taken together, the antitumor effect achieved in nude mice by the inoculation of T.Tn/hIL-2 cells is mediated by non-T non-natural killer cells.     

RGS8 accelerates G-protein-mediated modulation of K+ currents

Transmembrane signal transduction via heterotrimeric G proteins is reported to be inhibited by RGS (regulators of G-protein signalling) proteins. These RGS proteins work by increasing the GTPase activity of G protein alpha-subunits (G alpha), thereby driving G proteins into their inactive GDP-bound form. However, it is not known how RGS proteins regulate the kinetics of physiological responses that depend on G proteins. Here we report the isolation of a full-length complementary DNA encoding a neural-tissue-specific RGS protein, RGS8, and the determination of its function. We show that RGS8 binds preferentially to the alpha-subunits G(alpha)o and G(alpha)i3 and that it functions as a GTPase-activating protein (GAP). When co-expressed in Xenopus oocytes with a G-protein-coupled receptor and a G-protein-coupled inwardly rectifying K+ channel (GIRK1/2), RGS8 accelerated not only the turning off but also the turning on of the GIRK1/2 current upon receptor stimulation, without affecting the dose-response relationship. We conclude that RGS8 accelerates the modulation of G-protein-coupled channels and is not just a simple negative regulator. This property of RGS8 may be crucial for the rapid regulation of neuronal excitability upon stimulation of G-protein-coupled receptors.     

Reusing Urban Wastewater—An Alternative and a Reliable Water Resource

ABSTRACT

Fundamental concepts of reusing urban wastewater as an alternative and a reliable source of water supply are discussed, along with the categories for water reuse, planning methodologies, wastewater reclamation technologies, and economics. The rational basis for integration of urban reclaimed water into water resources planning is proposed and the safe use of reclaimed water is evaluated. Special attention is paid to tertiary or advanced wastewater treatment systems that are capable of producing essentially pathogen-free effluent for a variety of uses such as irrigation of urban landscape, flushing of toilets served by dual plumbing systems in large commercial buildings, and groundwater recharge for eventual potable reuse. The motivating factors for wastewater reclamation and reuse are summarized and the costs of water reclamation projects are discussed with several examples. The integration of this alternative water supply into water resources planning is proposed and the safe use of reclaimed water is emphasized.     

Protein Folding in the Presence of Water‐Soluble Cyclic Diselenides with Novel Oxidoreductase and Isomerase Activities

The protein disulfide isomerase (PDI) family, found in the endoplasmic reticulum (ER) of the eukaryotic cell, catalyzes the formation and cleavage of disulfide bonds and thereby helps in protein folding. A decrease in PDI activity under ER stress conditions leads to protein misfolding, which is responsible for the progression of various human diseases, such as Alzheimer's, Parkinson's, diabetes mellitus, and atherosclerosis. Here we report that water‐soluble cyclic diselenides mimic the multifunctional activity of the PDI family by facilitating oxidative folding, disulfide formation/reduction, and repair of the scrambled disulfide bonds in misfolded proteins.